1. Field of the Invention
The invention pertains to loose-leaf binders, more specifically to a loose-leaf binder of strong, inexpensive construction which temporarily binds papers in a resiliently biased spine.
2. Description of the Prior Art
FIGS. 1-4 show a prior art ringless spring-grip loose-leaf binder well known to the art and sold under various trade names, for example Avery Dennison model 96377 available in college book stores.
FIG. 1 is a front view of a prior art binder.
FIG. 2 is a perspective view of the binder of FIG. 1. A portion of one of the covers is cut away to show a construction of the binder.
FIG. 3 is a front view of the binder of FIG. 1 holding a booklet consisting of a quantity of loose paper sheets wrapped at one end by a flexible cover or folder.
FIG. 4 is a front view of the binder of FIG. 3 opened to release the booklet.
PRIOR ART binder 20 includes flexible longitudinal channel 21 forced closed by a plurality of circumferential U-shaped spring clips 33 along its length. Stiff covers 23 are attached by a pair of hinges 24 and 25 to the longitudinal edges 26 of the channel.
In FIG. 3, hinges 24 and 25 are biased toward one another by spring 33 and they clamp on folder 27 which extends into channel 21.
In FIG. 4, folder 27 is released from channel 21 and hinges 24 and 25 by folding covers 23 back around channel 21 and drawing them toward one another 28 which forces the hinges 24, 25 apart 29 by bending spring clip 33 apart about fulcrum 30.
Folder 27 is U-shaped, made of flexible paper or plastic, and is filled with sheets of paper 32. When the paper-holding folder is clamped between hinges 24 and 25 the part of each sheet of paper that is outside channel 21 is available for viewing.
Although the prior art binder serves the purpose for which it is intended, it is expensive and cumbersome to manufacture, requiring skilled hand labor to form the channel and to mount the spring clips around the channel. Opening the channel places great strain on the channel carcass by the spring, resulting in reduced operational life.
U.S. Pat. No. 1,443,522, patented Jan. 30, 1923 by H. G. Buchan describes a binder having two covers, and a plurality of U-shaped springs wrapped by a flexible binding that is wrapped over the ends of the legs of the U and fixedly clamped to the ends of the legs under a pair of longitudinal clamping tubes, each tube being split lengthwise. A length of binding extends from the split of each clamping tube and flexibly supports one of the two covers. Wedges are used to force the springs open so that elements of the binder can be assembled.